Updated: 11/10/2019

Appendicitis

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  • A 46-year-old man presents to the emergency department with nausea, vomiting, constipation for the past 2 days. He also complains of abdominal pain that initially started at the periumbilical area then traveled to the right lower quadrant. He is tachycardic, febrile, and mildly hypertensive on examination. A physical examination demonstrates a diffusely tender abdominal with reboud, especially at the right lower quadrant. 
Introduction
  • Clinical definition
    • medical condition characterized by the inflammation of the appendix, a vestigial structure located at the base of the cecum 
    • it is one of the most common causes of the acute abdomen
  • Epidemiology
    • demographics
      • most commonly occurs during the 2nd and 3rd decades of life
      • incidence of 233/100,000 and highest in the 10-19-year-old age group
  • Pathogenesis
    • the natural process involves initial inflammation of the appendiceal wall followed by local ischemia, perforation, and leading to abscess development or generalized peritonitis
    • obstruction of the appendix is the proposed primary cause
      • fecaliths (hard fecal masses)
      • calculi
      • lymphoid hyperplasia 
        • more common in the young
      • infectious process
      • benign/malignant tumors
    • obstruction of the appendix leads to an increase in luminal and intramural pressure leading to the thrombosis and occlusion of the small vessels in the appendiceal wall and stasis of lymphatic flow
      • bacterial overgrowth occurs with predominately aerobic organisms
    • the engorged appendix stimulates the visceral afferent nerve fibers at the T8-T10 level leading to the initial central/periumbilical abdominal pain
      • the latter localized pain at the RLQ occurs due to inflammation of the adjacent parietal peritoneum
Presentation
  • Symptoms 
    • abdominal pain  
      • initial periumbilical pain with migration to the RLQ
    • anorexia
    • nausea
    • vomiting
    • diarrhea
    • indigestion
  • Physical exam 
    • fever
    • McBurney point tenderness 
    • Rovsing sign 
      • pain in the RLQ with palpation of the left lower quadrant (LLQ)
    • Psoas sign 
      • associated with retrocecal appendix
      • RLQ pain with passive right hip extension
    • Obturator sign 
      • RLQ pain with right hip flexion followed by internal rotation
Imaging
  • Abdominopelvic computed tomography (CT) with IV contrast
    • preferred test in patients suspected with appendicitis as it has the highest diagnostic accuracy when compared to other imaging modalities
    • positive findings include wall thickening (> 2mm), periappendiceal fat stranding, appendiceal wall enhancement, appendicolith, and enlarged appendiceal double-wall thickness (> 6mm) 
  • Ultrasound 
    • preferred test in children and pregnant women due to its lack of ionizing radiation and IV contrast and can be performed at bedside
    • though results may be variable, patient- and operator-dependent
    • positive findings include focal pain over appendix with compression, noncompressible appendix with enlarged double-wall thickness (> 6mm), increased echogenicity of inflamed periappendiceal fat, and fluid in the right lower quadrant  
  • Magnetic resonance imaging (MRI)
    • indicated for pregnant women or older children who can tolerate the exam
Studies
  • Serum pregnancy test 
    • should be performed in all women of childbearing age prior to imaging that exposes a potential fetus to radiation and to rule out other causes of acute abdomen
  • White blood cell count with differential
    • often will demonstrate leukocytosis with left shift
Differential
  • Ectopic pregnancy 
    • differentiating factors
      • will have positive urine pregnancy test and perhaps positive pelvic ultrasound findings
  • Ovarian/fallopian tube torsion
    • differentiating factors
      • will appear on CT imaging
  • Renal colic 
    • differentiating factors
      • will appear on CT of the abdomen and will generally present with hematuria
  • Psoas abscess
    • pain to palpation
    • pain with stretching of the psoas muscle
    • diagnose with CT 
Treatment
  • Non-perforated appendicitis
    • appendectomy (laparoscopic or open) 
      • should be performed within 12 hours of diagnosis
      • laparoscopic approach is more common and popular
    • antibiotics
      • though there is growing popularity with antibiotic-alone therapy
  • Perforated appendicitis with hemodynamic instability, sepsis, free perforation, or peritonitis
    • emergency appendectomy
    • irrigation and drainage of peritoneal cavity
    • bowel resection if needed
  • Stable perforated appendicitis
    • initial nonoperative management
      • IV antibiotics
      • percutaneous drainage of abscess if present
    • rescue appendectomy for patients who do not respond to antibiotic
Prognosis, Prevention, and Complications
  • Perforation
    • leads to peritonitis
  • Periappendiceal abscess
    • most commonly due to B. fragilis
  • Pylephlebitis
    • inflammation of the portal vein
    • ↑ risk of thrombosis
  • Septicemia
  • Subphrenic abscess
    • fixes diaphragm on the right
    • tenderness over 7/8th ribs
  • Death 
 

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Questions (2)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
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